Prosthetic knee devices
A knee replacement is really a cartilage replacement. The knee itself is not replaced, only the cartilage on the ends of the bones. The replacement implants include a metal alloy on the bottom of the thighbone and polyethylene (plastic) on the top of the tibia and underneath the kneecap. The implant is designed to create a new, smoothly functioning joint that prevents painful bone-on-bone contact.
Your surgeon may elect to replace all or part of your knee, depending on your condition and the extent to which your knee is affected by arthritis.
Total Knee Replacement
Clinical History: Excellent Long-Term Results at 10+ Years
The appendix shows the long-term survivorship of Biomet’s AGC® knee system. Biomet also offers newer designs that have not been available for as long and thus do not have the same long-term data. All Biomet knee replacements are based on the basic design rationale of the AGC®, utilizing the same materials and concepts.
Materials: Molded Polyethylene Demonstrates Longevity
The articular surface of the knee, where the joint motion occurs, relies on polyethylene to reduce friction and allow motion. Polyethylene components for the knee are manufactured in one of two ways: direct compression molding (DCM) or machined from bar stock. The vast majority of Biomet’s polyethylene components for the knee are direct compression molded.
Unlike machining, direct compression molding does not tear at the polyethylene. The machining process can result in areas of high stress, which may over time lead to breakdown of the polyethylene. Direct compression molding greatly reduces these high stress areas, thus creating a potentially more durable component.
What About Oxinium®?
Oxinium® is a new process, used by another company, that turns the outside of the knee’s femoral component into a ceramic compound. While laboratory results on wear resistance are promising, there are no long-term clinical data on Oxinium®, so no one really knows how well it will work over time.
In order to reduce wear in its knee products, Biomet believes an appropriate engineering step is to improve the durability of the polyethylene component. That’s why Biomet uses direct- compression molded polyethylene, which has been shown to be more durable than machined polyethylene used by most other implant manufacturers.
Partial Knee Replacement
In patients with only limited knee arthritis, surgeons may elect to perform a unicompartmental (partial) knee replacement. Unlike total knee replacement involving removal of all the knee joint surfaces, a unicompartmental knee replacement replaces only one side of the knee joint. Knee osteoarthritis usually occurs first in the medial (inside) compartment as this side of the knee bears most of the weight. In knees that are otherwise healthy, a unicompartmental approach allows the outer compartment and all ligaments to remain intact. By retaining all of the undamaged parts, the joint may bend better and function more naturally.
The Repicci II® - The First Minimally Invasive Knee Replacement Procedure Developed in conjunction with John Repicci, MD, the Repicci II® is a partial knee replacement designed to remove as little bone from the knee as possible.
The entire surgery is performed through a very small incision, with minimal trauma to surrounding soft tissue. As a result, Dr. Repicci has reported that many patients leave the hospital on the day of, or the day after surgery, and are back to work within two weeks.1 The Repicci approach has demonstrated excellent results, with a 96% success rate after 5-8 years.2
The Oxford® Unicompartmental Knee System - Leading surgeons in Oxford, England along with engineers at Biomet, developed the Oxford® Unicompartmental Knee System. It's the only FDA-approved, free-floating meniscal partial knee system available in the United States and has been utilized throughout Europe for more than two decades.
In a healthy knee, the meniscus serves as a shock absorber between the ends of the bones. The Oxford is the first partial implant with an artificial meniscal bearing designed to glide freely throughout the knee's range of motion, more closely replicating normal movement. The free-floating nature of the device also improves durability of the implant.
Published long-term clinical results on the Oxford® Knee demonstrated a 98% success rate at 10 years, equaling the results of the most successful total knee replacements.3 Studies also show most patients experience a rapid recovery and more natural joint function.
Patellofemoral Knee Replacement with the Vanguard™ PFR
Designed by Walter F. Abendschein, M.D., the Vanguard™ PFR represents a unique and effective treatment for patients with severe pain in the front or middle of the knee from cartilage degeneration of the patellofemoral compartment (beneath the kneecap).
The advantage over a total knee replacement is that the healthy cartilage is not removed, making future total knee replacement easier to perform, if necessary. Another advantage is that the Vanguard™ PFR may be implanted utilizing a minimally invasive technique. Minimally invasive knee replacement patients typically recover more quickly than traditional joint replacement patients.
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